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Equipment for detecting, monitoring, measuring, displaying and recording pulse and heartbeat

  • US 4,164,937 A
  • Filed: 12/02/1976
  • Issued: 08/21/1979
  • Est. Priority Date: 12/02/1976
  • Status: Expired due to Term
First Claim
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1. Apparatus for detecting, monitoring and displaying the pulse and heartbeat of a human subject consisting of:

  • a. a transducer for engaging the finger and other parts of the human body to form optically created pulse signals from pulsatile blood volume changes using ambient light sources wherein said transducer consists of two photocells and a potentiometer, means for positioning the photocells to allow the photocells to detect ambient light transmitted through an engaged finger or other body parts and the photocells and potentiometer being connected as arms of a Wheatstone bridge circuit with said photocells being connected in a differential configuration to reduce the effect of changing and unregulated light sources and provide a suitable low level analog signal from minute photocell resistance changes and permit simple adjustments of the Wheatstone bridge circuit by varying the position of subject'"'"'s finger on the transducer, varying the effect of ambient light sources on the transducer and/or varying the potentiometer in the Wheatstone bridge circuit;

    b. comparator circuit means connected to the Wheatstone bridge circuit that senses the state of the Wheatstone bridge circuit and converts said low level analog signal to a high level digital output signal in response to the optically created pulse signals; and

    c. a light indicator connected to the comparator circuit means and operated by said comparator circuit means to produce a visual signal corresponding to the pulse and heartbeat.

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